Improbable, But Not Impossible
by Agents Are Us
Summary: On their vacation, FitzSimmons get stuck in a cave while snorkeling. Without enough oxygen to get back to shore, they become trapped between a rising tide and a terrigen crystal. It's confirmed: the universe hates them. [FitzSimmons, also includes slight genius!Skye]


**A/N: Hey, guys. So, this one-shot is based off of a prompt from Hyper-Blossom Z, where FitzSimmons get exposed to terrigen mists and become Inhumans! It's also got some Genius!Daisy in there. Hope everyone enjoys!**

* * *

Terrigenesis is a funny thing—only, no, it isn't.

They found that out on a warm summer day, when the leaves were green and still attached to their branches, and the sun was throwing golden-tinted light onto a sandy beach. They found that out at the bottom of the cold, dark ocean, when the sky was nowhere to be seen and the leaves were the last thing on their minds.

FitzSimmons—for the _second_ time in their lives, FitzSimmons was stuck at the bottom of the damn ocean, with no extraction plan. No-one knew where they were, and by the time they did, they would be dead.

"Lovely," Simmons said, pacing across the cave's smooth rock floor. Her diving equipment had been discarded near the entrance of the cave, and she was just about ready to throttle her companion.

Fitz was quietly blaming her for their entire predicament and moaning about the sandwich he'd had to miss to go snorkeling with her, all while showing an unprecedented level of unhelpfulness in the face of certain death.

How _Fitz_ of him.

"When the tide comes in, the cave will fill with water and we'll drown!" Jemma exclaimed, throwing up her hands in frustration.

"Not if the terrigen gets us, first," Fitz muttered, kicking at a stick of the blue crystal that was hidden at the back of the cave.

Simmons hadn't seen that. "Shit."

"Yeah, I know. When the water _does_ come in, it'll break the terrigen and we'll die. Or turn into Inhumans, but the probability of that is—"

"It's improbable, to be optimistic."

Fitz sat down on a rock by the crystal. "And to think," he started, volume and animosity rising with every word. "I could have been eating my damn sandwich."

Sighing, Simmons started to look around. "Come on, Fitz. There has to be a way out of here." She began pressing on different rocks, hoping to find _something_ they could use. "Check the equipment; see how much air is left. You know, we wouldn't even be in this mess if you hadn't been breathing so damn much."

"Well, the last time we were this far down into the ocean I spent months trying to _think_ straight again."

"In more ways than one," Simmons muttered, but her comment fell on deaf ears. Then, she said, louder, "I'm not swimming you up to the surface, again, Fitz. I don't think I'd be able to."

"What's that supposed to mean?" Fitz asked, looking up from the gauges.

In response, Simmons nodded to her right arm. There was a long gash running its length from the wrist to the elbow, deep and bleeding badly. Fitz hadn't noticed it yet because the dark blood looked like dirt against the black of her diving suit. But now he did, and with it he had to notice how fast her face was paling.

Immediately, his tone shifted from angry to helpful. "Sit down." Fitz came over to her. He tried to rip a piece of fabric from his suit but was unsuccessful.

"Use the—"

"Equipment. Right," Fitz finished, moving to get the sharpest piece he could find and using it to wear down the cloth. Eventually, he got a long enough rag and started wrapping it around Simmons' arm.

"What are we going to do, Fitz?" she asked, putting her head back against the cave's wall.

In response, the engineer shrugged a shoulder and sat next to her. "I can't swim as well as you—I think this trip proved as much. I'll get out of breath too fast and run out of air. And, even if there was enough oxygen for me to get to the surface, by the time I get there it'll to too late to come back down with help. Now, you can't swim, and we're stuck in a cave with an active terrigen crystal and the tide that will break it open in about… five minutes?"

Simmons laughed. "This is _not_ how I pictured this trip going."

Mind wandering to the small box hidden in his suit jacket back at the hotel, Fitz had to agree.

"Tell me the truth, Fitz… did you take one of the fish oil pills?" Simmons asked, breaking the uneasy silence that had fallen over them.

Putting an arm around her, Fitz shook his head.

"Me neither. So, it really is up to biology, now. And lineage."

"My mum always did say gran had eyes in the back of her head," Fitz offered. He failed to lighten the mood, but Simmons was thankful anyway.

A moment passed in silence.

"Why are we waiting, Fitz?" Simmons asked. Her face was paler still, and Fitz was beginning to worry she wasn't going to make it the next four minutes without passing out. "We should just… smash it. Now. Get it over with."

Fitz nodded, getting up and shuffling over to the blue crystal. It was really quite beautiful, against the grey stones. But, soon, it was swimming in a shallow pool, and Fitz's toes were covered by a thin layer of seawater.

It wouldn't matter soon, he reasoned. They had chosen.

Now, how to do it? Fitz took a minute to think, because he knew he couldn't touch it when that would almost definitely leave Simmons alone in this place.

He stomped on it, instead, and his body was covered in rock a second later.

There was no pause, no reprieve. Fitz didn't know if Simmons was experiencing the same thing as he was, or if she was already gone, or if he was bringing the cave down on top of her.

But, god, did it hurt.

A thousand tiny changes; a million pieces of his DNA being changed all at once; a billion possibilities: What would he become?

(And what about Simmons?)

Time is relative. Pain is not. He couldn't forget that, not now, because every second brought more pain, and it came like the ocean itself: in and out with the tide. There was nothing beside it. Nothing else to focus on, or think about.

The rock was falling on top of him, pressing his broken body down onto the hard place.

And then it was over. The rock started to fall off in pieces as big as his hand, crumbling down into nothing and taking away his support.

He fell.

He fell at the feet of a goddess.

Simmons. Inhuman. Alive. Fine. Inhuman. Beautiful. Goddess. Simmons.

"Jemma?"

She was picking him up, making him stand. Her hand was—there was something wrong with it. Webbing was fitted between her fingers, skin but not skin. Real but not real. Wrong but not wrong. Good. It was going to get them out of there.

"Fitz," she said, and her voice was strange. Muffled, or distorted. He could barely make it out, but there it was. Real.

She was alive, and so was he.

 _Okay_ , he thought. _Maybe not the_ _whole_ _universe is against us._

Simmons continued to pull him out of the cave, tugging at his arm. It was then he noticed hers was still bleeding—she didn't seem to mind, but the fabric's dark spot was slowly changing color. It was getting darker, and a black drop of liquid dropped off just as Simmons jumped into the water and started off to shore.

They were going to be fine.

* * *

"You'll be fine," Daisy said, looking up from her charts. She was still having trouble believing that both Fitz _and_ Simmons had joined the whole 'Inhuman group of people—yeah we don't have a real name yet but, hey! we have powers—this is cool' movement.

Simmons's neck was still a little alarming. Apparently, 'cool, underwater breathing!' wasn't enough, so she'd gotten gills. Great. Amazing. Saved FitzSimmons' lives. _Still_ a little weird to look at, especially when she got dehydrated and they started leaking her—now black—blood.

"Really?' Simmons asked, looking around the lab carefully. She didn't wait for an answer. "Because I think _better_ would be a more appropriate word. I don't think _anything_ that's happened can be described as _fine_."

Taking a step back, Daisy nodded. "Okay, I know this is hard, but you really _will_ be fine. I went through the same thing, and—"

"Did you?" Simmons asked maliciously. "Because, I don't recall you changing at all, physically. No, you just started making things _shiver_. But, it's exactly the same thing, isn't it?"

"I'll… give you some time," Daisy replied quietly, heading for the door. She told herself she shouldn't have been surprised. Simmons had never really been 'good' with Inhumans. Now she was one. It would be hard.

Simmons looked around her new quarters and set down on the white bed. "Right. Leave the monster where she belongs!"

* * *

"How is she?" Fitz asked, trying to gouge the expression on Daisy's face. With Bobbi on an extended mission and both him and Simmons taken out of the lab for the time being, she'd been assigned to pick up the slack.

Inserting a needle into his arm, Daisy shook her head. "Not good. Confused. Hurting. Depressed. She didn't get it as easy as you and me, Fitz. She had to change on the outside, too."

Fitz nodded and bit his lip. "I wish I could help her, but I can't even leave the pod without shutting down half the base's power. Last time we tried, I almost nuked Russia."

"I remember like it was yesterday. Because it was. And it's only been three days since you changed. You'll get a hold of it, and in the meantime we're making some glasses for you to wear."

"Like the gloves?"

"Like the gauntlets," Daisy corrected him. "They'll help you control your powers, not hide them."

Fitz nodded and looked up at her. "Thank you," he said sincerely before rolling the sleeve of his shirt down again.

Leaving with a brief smile, Daisy said, "You're welcome."

* * *

They say—well, Lincoln said—that each Inhuman got their powers for a reason. To fill some kind of need in the species.

Well, Simmons figured pretty early on that _her_ purpose was so save Fitz, that day in the cave. Fitz's 'purpose' came in swift procession, merely a week later.

"What's happening?" Fitz asked Daisy, alarmed, as the female Inhuman started entering the code to open his pod.

In full tactical gear, Daisy pulled him out and into the crack between pods. "AIDA. She's attacking. Making more of herself. May's one. We need your powers."

"I can't control them," Fitz reminded her, starting to wring his hands together.

As if to prove his point, a light above them sparked out.

Daisy shook his shoulders lightly, making him concentrate on her instead of the light. "Just… focus."

So, Fitz did. More lights went out.

"Okay, stop focusing!" Daisy said, wincing as lightbulbs shattered. "There's—there's a lot of components to her. A lot of things… can you sense them?"

Fitz could. He could feel every single part that made AIDA, but he could also feel the pieces of the base, the pieces of every single piece of technology _in_ the base.

"There's too many," he said, holding his head. His _eyes_ hurt. "I can't tell what's her and what's everything else."

Quake nodded. "Okay. I can help with that."

They left the space between containers and Daisy led them to a bigger hallway. While they walked, she continued talking to him. "When she finds us, I'll quake her. Then you just need to focus and—"

A light popped out above them.

"That should happen."

It didn't take long.

"She must have scanned the floor," Fitz explained, backing up against the wall. Suddenly, it wasn't there, and his back was pressing against metal.

 _Shaking_ metal.

Fitz was so nervous he didn't have to concentrate. "Off!"

So, she shut down.

"That was… surprisingly easy," he admitted, calming.

Then AIDA started to turn back on and Daisy quaked her until there was nothing but rubble.

* * *

They let Fitz out after he disabled AIDA, but Simmons was still stuck in containment days later.

They were scared she'd try to leave.

God, she wanted to.

Fitz came to see her every day, and he only left to work or sleep. That was nice, but the sentiment was marred by the glass between them. They wouldn't let him in, just like they wouldn't let her out. But that was good. She was sick. They had to protect the normal people.

"They want to send you to a training facility. Have you talk to a doctor," Fitz informed her, about a week after the AIDA incident and two weeks after terrigenesis.

Jemma nodded, head tilted back against the bedframe. "They want to send me to the shrink."

"Can you blame them? You haven't been yourself, Jemma."

"That's because I'm not myself, Fitz. We should have died in that bloody cave!"

She'd been thinking it over for the past 13 days, 11 hours, and about 42 minutes. How they should have gone out, fading fast at the bottom of the ocean.

"How can you say that, Jemma?! After you saved me; after I stopped AIDA. May would still be replaced with an _android_ if it weren't for us."

"You, you mean. You, Fitz, the hero. _You_ saved everyone, and I saved _you_. Those were our purposes, Fitz. And, please, name one Inhuman who has lived past their usefulness."

Fitz didn't answer. Fitz didn't answer because he was punching numbers in the console and making the doors open and coming in and then his arms were around her and then she was standing.

He looked like he was going to hit her. Good. She deserved it.

But then his hands were soft and she was warm and she didn't deserve this and then she did. She wondered if this would lift her heavy heart and make it human again.

Then, when he let go, nothing changed.

And Simmons started to wonder if nothing needed changing.

* * *

When Simmons started to show signs of mental improvement, her physical symptoms got better, as well. They let her back into the lab a few weeks later, under the stipulation that she saw a therapist. It helped, a bit. That, and studying like mad.

Simmons wasn't _that_ worried about her lab. Fitz was there, and Daisy could handle it. She hoped. Anyway, any problems to the lab itself could be easily fixed with a bit of alphabetization and bleach. The lab techs, on the other hand…

" _What_ did you do to them?!"

Daisy winced. "Well, you see, I was doing this experiment with the cube—you remember the cube from the orphanage? Well, we got it back, and I was doing some experiments and—"

"You de-aged them all?!" Simmons asked, taking a drink of water so her tone would come through loud and clear.

Fitz chose then to come in, goggles shading two circles around his eyes red. "Yes, well, don't worry, Jemma. We're going to re-age them as soon as they finish building your hydration bracelets. Nothing like an incentive," he said, talking to one de-aged scientist in particular.

She jumped, but kept working. When he walked away, there was a smoking, burnt hole in her lab coat. Daisy quickly gave her some salve. They were always close to running out, these days, and most agents had experienced some kind of electrical burn.

"Really, we should just keep them like this. The goons never worked, anyway."

As he spoke, the lights flickered, but no-one said anything. Fitz was still having trouble controlling his technopathy, and it was making him increasingly irritable. The red-tinted goggles helped with the headaches and x-ray parts, at least.

"Now, Fitz," Jemma started. "Didn't we talk about child labor laws?"

Daisy grinned, turning away to her computer and shrugging off the itchy lab coat they were making her wear. FitzSimmons was back.

* * *

Fitz knew he probably shouldn't have rented out the whole restaurant again, but he did anyway. Simmons deserved not to be stared at by anyone but him, so he paid off the waiters and kitchen staff as well. Just in case.

He shouldn't have worried. Jemma wore a nice cream shirt with a high collar and a pair of black leather pants, covering her neck. The fingerless gloves on her hands matched her red jacket. She drunk enough water to be comfortable, and Fitz knew that tonight was going to go perfectly.

The square little—not _too_ little—box dug into his side reassuringly.

That's why, when Simmons surprised him and proposed, he said yes and pulled out his engagement ring for _her_. Because it was meant to happen, just as they were meant to fill a place in the Great Inhuman Equilibrium.

Together.

* * *

 **A/N: Thanks for reading, and thanks to Hyper-Blossom Z for the prompt!**


End file.
